The present invention relates embedded nonvolatile memory (eNVM) and, more particularly, to protecting data stored in eNVM from corruption due to an electromagnetic-compatibility (EMC) event, such as electromagnetic interference (EMI), electrostatic discharge (ESD), and the like.
The term “electromagnetic compatibility” (EMC) refers to the ability of electrical equipment in general and electrical circuits in particular not to behave unacceptably when subjected to various types of interference, including EMI, ESD, and other electromagnetic disturbances. For example, certain EMC measures can be taken to address susceptibility and/or immunity issues in an integrated circuit (IC), with the general purpose being protection of the IC from disruption and/or breakdown due to an EMC event. Example EMC measures may include customized control of operating regimes, circuit-design constraints and/or features, EMC testing, EMI shielding, etc.
Embedded nonvolatile memory (eNVM) is an important IC component that adds flexibility to electronic products and helps to shorten time to market. For example, eNVMs are widely used in a variety of microcontroller applications in automotive, mobility, and security markets due to the eNVM's ability to support relatively high system speed via fast code access, in-system and/or on-board re-programmability of code and data storage, relatively low power consumption, and real-time controllability of the IC functions. However, a known problem with some eNVM designs is that a moderately strong EMC event may be capable of toggling certain critical eNVM control signals in a manner that causes the data or program stored in the eNVM to be uncontrollably changed, e.g., erased or randomly reprogrammed. In most cases, such uncontrollable changes precipitate a complete breakdown in the operation of the corresponding system-on-a-chip (SoC). In some systems, such as a moving vehicle, such a breakdown can be extremely dangerous, as it can compromise the safety of the occupants.